Delay fuse for drop bombs



-Feb.,21,=19as. D. L. WOODBERRQIIY 1,898,073

DELAY FUSE FOR DROP BOMBS Filed Sept. 20 1.926

7 I "v v. I

MAMA

Patented Feb. 21, 1%33 DAVID L. WOODBERRY, 0F BALTIMORE, MARYLAND, ASSIGNOR TO SECRETARY OF WAR OF THE UNITED STATES OF IGA DELAY FUSE FOR DROP BOMIBS Application filed September 20, 1926. Serial No. 136,658.

(GRANTED UNDER THE ACT OF MARCH 3, 1883, AS AMENDED APRIL 30, 1928 3 370 0. G. 757) The invention described hereinmay be manufactured and used by or 'for the Government for governmental purposes without the payment to me of any royalty thereon.

The subjectof this invention is a delay fuse for drop bombs.

The object of the present invention isthe provision of a fuse for drop bombs which may be set to explode the bomb at a predetermined interval after it has been launched. When a bombing plane or squadron passes over a favorable target the hostile troops in the vicinity will seek shelter thereby limiting the destructive force of the bomb to the demolition of property and equipment.

The fuse forming the subject of this invention may be set to function hours or days after impact, the exact time for the explosion of the apparently harmless bomb to occur for instance at some period of the day when it is known that troops will be in the locality. The timing mechanism for securing this result contemplates the novel incorporation of a frangible container, rupturable during flight to allow a solvent of predetermined:

strength tobe liberated and have access to a soluble member which holds the firing mechanism inoperative.

The fuse is further so constructed that upon any attempt to remove it from the bomb for the purpose of rendering the bomb inoperative immediate detonation of the explosive charge will result.

Safety is obtained by arranging the setting mechanism so that the fuse can not be armed until the bomb has been released from the plane. Provision is also made whereby the fuse may be assembled to the bomb with the rear cap and stabilizers in place.

To these and other ends, my inventionconsists in the construction, arrangement and combination of elements, described hereinafter and pointed out in the claims forming a part of this specification. l A. practical embodiment of the invention is illustrated in the accompanying drawing, in

which Fig. 1 is a longitudinal sectional view of a fuse constructed in accordance with the invention;

Fig. 2 is a sectional view on the line 2-2 of Fig. 1; I

Fig. 3. is a detail end view of the bolt;

Fig. 4 is a detail View showing the grapeseed lock.

Referring to the drawing by numerals of reference: a

In carrying out the invention the bomb consists prior to the assembly of the fuse ofa shell 6 on which is fixed a rear cap 7 having the usual stabilizing fins 8. The shell and cap are suitably apertured to permit insertion of a fuse, the inner end of which'is dis- .posed in a fuse seat liner or thimble 9 which may be assembled to the shell prior to fusing Ehe bomb or it may be assembled with the use.

The fuse comprises a body or casing which for convenience is formed in two parts and consists of a sleeve 10 provided for threaded attachment to the liner 9 and a centrally disposed member 11. To the inner end of the casing is secured a block 12 containing a booster charge 13 while on the outer end of the casing is detachably connected, as by threading, a fuse head 14 which is formed with a tubular extension 14a, and the extremity of which head, adjacent the, casing member 11, is closed by a plate 15 retained by a Mounted transversely in the casing is a slidable bolt 17 carrying a primer 18 and a detonator 19. The bolt is normally held in the unarmed position with the primer detonator out of line with the booster 13 and firing pin 28 by means of one or more release rods 20 engageable with the bolt to hold it against the action of the springs 21. The release rods are carried by a plunger 22 mounted between the casing member 11 and fuse head 14 and normally held in the energized position, with the release rods in engagement with the bolt, by means of a disk 23 secured in the plate 15 of the fuse head in any convenient manner and serving as a restraining member against which the stem 22a of the plunger is in contact. The disk 23 is of a material such as celluloid which is soluble, and in the operation of the fuse is to be subjected to a solvent 24, for example, acesolvent is confined in .tone, of a predetermined strength to disintegrate the disk in a stated period of time. The

an annular chamber 146 in the fuse head, the inner wall of said chamber being of glass or some other frangible material. Liberation of the solvent is effected by means of a spindle 26 carrying vanes 27 which unthread it during flight in a well known manner, and in order to facilitate and insure breaking of the glass wall during the longitudinal movement of the spindle, the wall is preferably of tapered form. The spindle at its lower. end is provided with an enlarged head 26a removably eyed to permit its separation and allow the vane unit to fall clear when its task is accomplished. It will be noted that when the vane assembly is in place in the fuse the head 26a is in position to prevent suflicient movement of the plunger 22 to withdraw the releasev rod 20 from the bolt so that even should accidental liberation of the solvent result in dissolution of the disk 23 the fuse can not function until after the bomb is launched and the release pin 27a, holding the vanes against rotation, is removed in the accustomed manner.

The firing pin 28 disposed in the casing member 11 rides on the bolt 17 with its point in a groove 17a in the bolt, thereby preventing the bolt from rotating in its movement to armed position. The firing pin spring 29 presses the pin against the bolt so that as soon as the opening 30 in the bolt presents itself, the firing pin enters therein and sets off the primer and this will automatically occur when the release rod has been withdrawn.

The casing 10 is held against removal by a number of grape-seed locking members 31 which are so disposed in recesses 82 to permit threading but to prevent unthreading of the casing with respect to the liner 9. Consequently, when an attempt is made to remove the fuse, only the fuse head 14 will be moved,

andsince the plunger underthe influence of.

its spring will follow this movement the release rod will'be withdrawn and the bolt armed. The firing pin thenautomatically sets off the primer before the fuse head ran be removed. i

As a means of placed in-the bomb without removal of the rear cap, there is provided an elongated tubular member 33 fixed to the fuse head and formedwith a collar 34 which when the fuse is in place will rest against the cap closing it and securely holding it in place.

Solvents of various strengths corresponding to the delay periods may be conveniently kept in vials and the fuse is preferably charged just prior to assembling it to the bom Safety screws 35 and 36 are provided for an obvious purpose and are removable before fusing the bomb.

permitting the fuse to be.

I claim:

1. A time fuse for bombs, including a casing, a booster in one end thereof, a fuse head threadable in the other end and including an annular chamber having a tapered frangible wall, a solvent of predetermined strength in the chamber, a plunger mounted between the casing and the fuse head, a slidable bolt mounted transversely in the casing, detonat'or in the bolt, a release rod carriediby the plungerfor normally holding the bolt in unarmed position, the fuse head and restraining the plunger against movement, a firing pin for automatically setting off theprimer as the bolt arms, means removable during flight for breaking the frangible'wall to liberate the solvent, said means also serving when in place to means for retainingthe casing whereby on removal of the head the plunger may withdraw the release rod and permit the fuse to function.

2. A time fuse for bombs including a casing, a slidable bolt mounted transversely in the casing, a primer in said bolt, a plunger carrying means for normally holding the bolt in unarmed position, a soluble member for restraining the plunger against movement, a container adjacent the plunger and having a frangible wall, a solvent of predetermined strength in the container and means operable during flight for rupturing the wall and liberating the solvent, said means also serving when in place to assure retention of the plunger.

3. A time fuse forbombs, including a casing, a slidable bolt mounted transversely in the casing, a primer in said bolt, a plunger carrying means for normally holding the bolt in unarmed position, a soluble member for restraining the plunger against movement, a container adjacent the plunger, a solvent of predetermined strength in the container and meansoperable during flight..for liberating the solvent, said means also serving when in place to assure retention of the plunger.

4. A time fuse for bombs including a casing, a slidable bolt mounted transversely in the casing, a primer in said bolt, a plunger carrying means for normally holding the bolt in unarmed position, a soluble member for restraining the plunger against movement, a container ad acent the plunger, a

solvent of predetermined-strength in the container and a non-soluble member normally supporting the soluble member and movable during flight for liberating the solvent.

5. A time fuse for bombs, including a casing, a slidable bolt mounted transversely of the casing, a primer in said bolt, 2. plunger carrying means for normally holding the bolt in unarmed position, a member for restraining the plunger against movement, a confined chemical of predetermined strength a primer.

a soluble disk carried by lily i017 liberatl i and means eraiiie luu ing the ch g to grate the restrainmg member. .7

6. A time fuse for bs mcludmg 5 ing, a slidable bolt anted transversely o th casing a prime n said bolt, a plunger ca i means fa normally holdlng the bolt i unarmed JSltlOIl, a member for ret i i the pger aga1nst movement, a h b i the sing for holding a chemical f predetermird strength and means for 11bti the .emic'al to disintegrate the restraining m 613 i 7, A ti fuse including a casing, a slid- 15 abl b lt ,iounted transversely in the casing, a i m said bolt, a plunger in the casing carryirg means for normally holding the bolt i, unarmed position, a member for restraining the plunger against movement, a firing pin mounted in the casing to automatically set 01f the primer as the bolt moves to armed position, a timing'element controlling the restraining member and means supporting a restraining member and movable to bring the timing element into operation.

8. A time fuse including a casing, a slidable bolt mounted transversely in the casing, a primer in said bolt, a plunger in the casing carrying means for normally holding the bolt in unarmed position, a firing pin mounte in the casing to automatically set off the primer as the bolt moves to armed position, a timing element controlling the movement of the plunger to functioning position and positively movable means for bringing the timing element into operation.

9. A time fuse for projectiles including a member securable to the projectile against removal, a fuse head unscrewable from said member and means operable on unscrewing of the head for inoperating a delay time mechanism to provide for immediate detonation. 10. A time fuse embodying a firing mechanism, a timing element associated therewith and operable during removal of the fuse from a projectile to permit functioning of the firing mechanism.

11. A fuse embodying a firing mechanism and means associated therewith and actuate during removal of the fuse from a projectile to permit functioning of the firing mechanism.

12. In a fuse, a casing, a firing mechanism in the casing, a soluble member restraining the firing mechanism, an annular chamber having a frangible wall, a solvent in the chamber, and means operable to break the frangile wall. DAVID L. WOODBERRY. 

